Adaptors no problem, why 100 to 110....114.3 would be a better option for getting a wider variety of wheels to suit. I think bolt on adaptors are legal so long as the track doesnt go past the allowed 1" extra but correct me if I'm wrong.
Importing pre-1988 cars fairly easy, go here for starters;
http://www.infrastructure.gov.au/roads/veh...cles/index.aspx
If you need any futher info just PM